The present invention concerns a filter membrane of a multi-layer configuration for filtration of a medium, a hollow fiber comprising the filter membrane, and a filter module.
US 2010/0112267 A1 discloses a single-layer hollow fiber membrane for filtration of gases. This hollow fiber membrane is comprised of porous material.
DE 10 2005 008 900 A1 discloses a filter module with a plurality of hollow fibers. These hollow fibers are comprised of ceramic material. The hollow fiber membrane can be of a multi-layer configuration, in particular of several potting compounds.
DE 10112863 C1 discloses a filter module of ceramic Al2O3 green fibers.
Also, multi-layer ceramic hollow fibers are known which are formed of oxide ceramic materials, for example, of Al2O3. These fibers however clog gradually so that the diffusion flow is impaired.
Moreover, hollow fibers are known which are formed of non-oxide ceramic material. However, these must be produced very expensively. In case of silicon carbide hollow fiber membranes, they are produced at firing temperatures of more than 2,000° C. with exclusion of oxygen.
It is thus the object of the present invention to provide a filter membrane, a hollow fiber, and a filter module that can be produced inexpensively and exhibit better filtering properties in comparison to oxide ceramic hollow fibers.